Anode



y 1932- G. DUBPEIRNELL ANODE Filed Nov. 13, 1929 JNVENTOR. o ge Dab Derive Patented July 19, 1932 UNITED STATES PATENT OFFICE GEORGE DUBPERNELL, OF ANN ARBOR, MICHIGAN, ASSIGNOR TO UDYLITE PROG'ESS COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN AN ODE Application filed November 13, 1929. Serial No. 406,776.

This invention relates to anodes for an electro-plating bath. In the prior application of Messrs. Jesse O. Wagner and Alfred S. Ascher, Serial No. 429,880 filed February 20, 1930, there is described and claimed an anode for electro-plating which involves the use of an anode container or basket in combination with relatively large soluble metal anode units of regular configuration.

The present application involves an improvement over the anode described in the above application by virtue of the use of an improved container, which is easier to construct, forms a better and more reliable con- 1 ductor for the electricity, and in which the open spaces in the container can be coordinated with the size of the soluble unit as it dissolves, so as to get a maximum exposure of the soluble anode unit and at the same time prevent its falling into the bath as it becomes smaller in dissolving. Furthermore, the container is stronger and not subject to permanent distortion by reason of being dropped or suffering blows.

In the drawing:

Fig. 1 is an elevation of the anode partly in section.

Fig. 2 is a fragmentary sectional view showing the basket mounted in the bath.

The basket comprises a wire helix of heavy wire a; the convolutions are fairly widely spaced at the top of the basket but as they run down toward the bottom of the basket they approach closer together so as to coordinate the cage with the smaller size of balls toward the bottom of the basket.

The soluble metal anodes are preferably in the form of spheres or balls 6, of the metal to be deposited, and are, of course, soluble in the bath. This anode is intended primarily for electro-plating in baths composed largely of the double cyanide of sodium or potassium and another metal, and usually containing also an appreciable proportion of free cyanide. In such a bath the helical wire container may be of steel and, in fact, can be of steel in nearly all baths where a double cyanide solution is used as the electrolyte. For other baths, such as acid baths, the anode This is very desirable in the operation of an basket or container can be constructed of a different metal, such as lead in some cases.

It is desirable to have the soluble anode unit as fully exposed to the electrolyte as possible, both for the corroding action of the electrolytc and the free discharge of the metal ions but this exposure must be limited by reason. of the possibility of the escape of the anode units when they get small by corroding away. The helical wire basket very nicely accomplishes this end in combination with the stack of relatively large soluble units. The cage can have the convolutions very much closer together at the bottom where the balls become proportionately smaller, as is clearly shown in Fig. 1, and at the very bottom the convolutions can be made to touch one another so as to prevent the escape of even a fra ment of the balls, and the extreme bottom 0 the container may be closed by the end 0 of the strap 03.

It has been explained in the earlier Wagner-Ascher application why relatively large soluble units of regular dimension and configuration are desirable in electro-plating. Sufiice it to say here that it gives a regularity and" a constancy of anode area that so far as we know has not been accomplished in any other way. It also tends to give a constant'delivery of current to each electrode and consequently keeps the current density per unit of anode surface substantially constant throughout the soluble anode units.

electro-plating bath to get the best results.

The wire helix is very cheaply manufactured as it virtually requires nothing but a winding of the heavy steel wire. Furthermore we find that this affords a freer path for the current to each ball unit than is possible with a wire mesh or expanded metal electrode basket for the reason that the cross section 'of the conductor is much greater and of course, the resistance varies inversely as the cross section of the conductor. Furthermore, the cage is not easily injured by dropping or being struck a blow, as a heavy steel wire is used which does not under ordinary load take a permanent set.

It is very desirable to have a basket or container that will not dent, for one that will may often prevent the downward feed of the balls if the operator does not observe the dent.

The strap d is hooked over at the upper end to lie over the conducting bar. It runs the entire length of the helix and preferably each of the convolutions is welded to the strap Where the convolution crosses the strap.

Of course it will be apparent that it will be possible to make the cage of non-electric conducting material'and aiford other means for supplying the balls with the electrical current, although we prefer to make the cage a conducting member, Hence we do not wish to-be limited to an electric conducting cage in the claims except where such a limitation is expressly stated in the claims.

What I claim is:

1. An anode for use in electrolytic baths comprising a heavy steel wire helix with varying spacing decreasing toward the bottom, and a plurality of balls substantially larger than pellets of the anode metal contained in the basket in a vertical stack and replenishable as they feed downwardly, the said balls as they become smaller arriving at a position in the cage where the spacing between the convolutions is smaller.

2. A composite anode for electro-plating baths comprising a perforated insoluble container, and a plurality of substantially spherical metal units soluble in the electrolyte forming a stack in the cage and arranged to be replenished as they dissolve, the stack of metal units having a gradual variation of cross-sectional area from one end to the other, the metal units being substantially larger than pellets and the openings in the said container having a variation in size corresponding relatively to the variation in cross-sectional area of the metal units forming said stack. a

3. A composite anode for electro-plating baths comprising an open helical coil insoluble container, and a plurality of metal units soluble in the electrolyte forming a stack in the cage and arranged to be replenished as they dissolve the stack of metal units decreasing in cross-sectional area from one end to the other, the openings between the successive convolutions of the open helical coil be ing gradually decreased in size from one end of the container to the other corresponding with the variations in the cross-sectional area of the soluble metal anode stack.

4. A composite anode for electro-plating baths comprising an open helical coil insoluble container having the openings between the successive convolutions of the coil gradually decreasing from the top to the bottom, and a plurality of substantially spherical. metal units soluble in the electrolyte formmg a stack in the said insoluble container and arranged to be replenished as they dis face to the current action throughout its en tire travel from the top to the bottom of the container.

In testimony whereof, I have afiixed my signature.

GEORGE DUBPERNELL. 

